There are good reasons for employers, employees, governments and members of the public to be concerned about hazardous substances. Hazardous substances by their very nature have potential to cause harm to people, property and the environment.

Consider the following case studies.

CASE STUDY 1 The Sign

Dangerous goods were being repacked by a suburban company which handles hazardous materials and recycles and consolidates agricultural and analytical chemicals. A total of 15 kg phostoxin tablets (aluminium phosphide) were packed into plastic pails, and placed on pallets to await dispatch by road transport.

During the evening, a fire broke out in the depot area. The MFB was notified, and on attendance they checked the HAZCHEM signs (composite warning signs) to determine the most suitable extinguishant for use on the fire. The HAZCHEM signs indicated the use of water fog, which the fire officers adopted. The fire was quickly extinguished.

However, the phostoxin tablets reacted with the water used to extinguish the flames, resulting in the generation of the poisonous gas, phosphene. A secondary incident had begun.

The product pails were melting in the heat of the reaction. They were carried by fire officers wearing full breathing apparatus to recovery drums, and removed from the enclosure of the depot to a safe position in the open air. The fire service and the VWA emergency response officer waited for some time to ascertain the magnitude of the reaction. The drums were then deluged with water to effect a vigorous but shortlived reaction. The EPA was required to supervise a clean up.

Prior to the incident, there had been some confusion amongst the site management as to the classification of the phostoxin tablets (whether Class 4.3 DANGEROUS WHEN WET or 6.1(a) POISONOUS). However, given the relatively small amount of product at the premises, and the pending dispatch of the product, the occupier was not duly concerned with altering the HAZCHEM sign to indicate the presence of the small quantity of product in the warehouse.

Thus, the resultant composite warning sign was misleading at the time of the fire, and indicated an inappropriate extinguishing agent for a fire.

The cost of amending a HAZCHEM sign is minimal. One complete sign costs less than $25 dollars to prepare.

Would you have changed the composite warning notice to reflect the presence of this relatively small amount of substance?

The company’s inactivity exacerbated the incident, extending the incident time by several hours, and costing the company a great deal more in the form of fire service accounts.

Fire service

$ 23,000

Cleanup and disposal (performed by company personnel during their day off)

$ 500

Downtime

1 day

Repairs to equipment, building

$ 1,000

TOTAL $24,500

CASE STUDY 2 The Fire

Personnel at a transport warehouse were in the process of repacking damaged bags of goods in the form of a micro-fine powder. The repackaged containers were being stacked on to pallets and secured with shrink wrapped plastic film.

The powder being repackaged was combustible. The repackaging activity had produced a large amount of dust in the immediate vicinity.

The loading of the pallets and the shrink wrapping process was being performed in the same area as the repackaging. A gas flame was being used to shrink the plastic wrap.

What happened next is self explanatory.

The combustible dust was ignited by the flame torch, resulting in a dust explosion. The ensuing fire spread to other goods in the warehouse.

The warehouse contained large quantities of combustible products, mostly non-dangerous goods. Smaller quantities (although still several tonnes) of dangerous goods, including flammable, toxic or corrosive products, were also present.

The fire was one of the biggest Victoria has experienced. The warehouse collapsed and most of the products stored inside were destroyed or damaged beyond recovery.

The smoke from the fire was carried aloft to more than one kilometre. The fire caused a major community outcry, calling for stricter controls on such premises, and community condemnation of the company involved.

Primarily, the fire was caused by use of unsuitable equipment in a hazardous area.

But some other features exacerbated the fire, once it had erupted:

A ruptured fuel line within the premises hampered early control of the fire. Hydrants were not properly equipped and were in disrepair. Hose reels were not provided. Ventilation in the area was not adequate. Placarding was not provided.

Were the following costs and inconveniences unavoidable to any extent?

Cleanup, including 5 megalitres of contaminated firewater

1 month

Fire Services involved

475 officer

Police helicopter

58 officers and

Safety agencies (VWA, EPA, Melbourne Water, PMA)

approx. 40 officers

Damage to neighbouring property

$210,000

Costs, including loss of product, equipment, downtime, other direct and indirect costs.

Approx. $3,200,000

TOTAL $3,410,000

Consider the following statistics:

It is thought than more than 40 Australians die each week after being exposed to hazardous substances at work. The official annual toll is 2300.

Workplace Killers*

(*Death blamed on workplace exposure to diseases and poisons).

Cause of Death

Males

Females

Cancers

1133

175

Major Disease

601

310

Dust Disease

47

1

Poisonings

27

7

TOTAL

1808

493

* Source Worksafe Australia.

HAZARDOUS MATERIALS

What are hazardous materials?

To be a hazardous material or substance, the substance must have physical or chemical properties that make it

There are strict requirements for the manufacture, storage, transport, transfer, sale, use, handling and disposal of hazardous materials. The legislation follows international models developed by the United Nations and national models developed by WORKSAFE Australia (the National Occupational Health and Safety Commission). This approach makes sure that hazardous materials and dangerous goods can be manufactured in Australia, and transported anywhere in the world to world standards.

Dangerous Goods Act 1985

This is the principal Act for dangerous goods in Victoria. It allocates responsibilities to owners and occupiers of premises where dangerous goods are stored or used. The transportation of dangerous goods by road and rail is provided by the adoption of the Australia Dangerous Goods Code. Occupational Health and Safety Authority Inspectors under this Act have wide powers of entry, seizure, requests of assistance, and inspection under the Act.

Dangerous Goods (Explosives) Regulations 1988;

Details the special requirements when handling explosives.

Dangerous Goods (Storage and Handling) Regulations 1989;

Details requirements for the storage and handling of dangerous goods in workplaces.

Dangerous Goods (Liquefied Gases Transfer) Regulations 1987

Provides the requirements for the transfer of liquefied gases.

Dangerous Goods (Transport) Regulations 1987;

These regulations are the Victorian specific requirements not covered by the Australian Code.

This legislation covers the production, transportation, disposal and treatment of waste.

Occupational Health and Safety Act 1985 and Regulations:

Outlines roles and responsibilities of employer and employee in workplaces. The responsibilities of manufacturers and suppliers to provide information and instructions on safe use of substances and equipment.

Over the length of this course terms will be used that you may not be familiar with. The following is a list of some of those terms and what they mean:

(Source: Guide to Chemicals in Australia, produced by ACTED. (See www.vianet.net.au/~acted.)

Acute Toxicity

Acute toxicity means a toxic effect which occurs immediately or shortly after a single exposure. Contrast to chronic toxicity. It does not indicate the severity, only the duration of exposure.

Asphyxiant

A substance which, as a gas or vapour, can cause suffocation due to a lack of oxygen.

Biological Exposure Index

A biological exposure index is defined by Worksafe as a warning level of biological response to a substance or agent, or warning level of the substance or agent or its metabolites in the tissues, fluids or exhaled air of an exposed worker.

Chemical Abstracts Service Number (CAS RN or CAS No.)

An internationally recognised registration number assigned by the Chemical Abstracts Service to uniquely identify either a chemical, a group of similar chemicals or a mixture (including a fortuitous mixture such as an oil refinery product).

The CAS Number (sometimes described as a Registry Number or a RN) consists of up to nine digits and provides an accurate way for retrieving a substance from a computer database. The CAS number is simply a reference number and, unlike the UN number, cannot be linked to any particular chemical or physical properties.

Chronic Hazardous Substances

A class of dangerous goods used in Western Australia (Class 10 to become Class R) consisting of any substance not elsewhere specified, which are carcinogenic, hazardous, mutagenic or teratogenic. Specific storage and handling procedures apply.

Chronic Toxicity

A toxic effect which is demonstrated after repeated or prolonged exposure which need not occur immediately after cessation of exposure.

Exposure Standards (ES)

Exposure standards detail levels of airborne concentrations of substances which, according to current knowledge, do not impair the health, or cause discomfort to the workers. Exposure standards are generally expressed as a time-weighted average (TWA) concentration of a substance over an eight-hour working shift, and applied to an eight-hour day, for a five-day working week over an entire working lifetime. TWA permit excursions above the limit provided that they are compensated by equivalent excursions below the limit during the workday.

Fume

A suspension of liquid or solid particles in the air formed by condensation of vapours from heated substances (including metals produced during welding). Also includes the vapours produced by a decomposition reaction. Moisture in the air often promotes the formation of mists and fumes by reactions.

Gas

A substance which at ambient temperature and pressure appears as a gas, meaning that the molecules of the substances travel free in open space. Formless, can be changed to the liquid or solid state by cooling and/or pressure.

Hazardous Materials

Includes dangerous goods and hazardous substances as defined in State legislation which includes other substances which, on release, could threaten health or the environment.

Hazardous Substance

A substance which has the potential through being used at work to harm the health or safety of persons in the workplace including substances which may be produced in the workplace (eg. from welding rods, plastic processing etc.)

Hazchem Code

The Hazchem (emergency action) code provides information to emergency services in terms of type of extinguishing agent, protective equipment, spill containment, prospects for violent reaction, and need for evacuation. The code consists of a number followed by a letter, and an optional third letter ‘E", eg. 3YE.

Manifest

A statement on stored quantities primarily for emergency services as defined by the National Code of Practice for Emergency Services Manifests.

Material Safety Data Sheet

A document describing the properties of a substance defined in the National Commission’s National Code of Practice for Completion of Material Safety Data Sheets.

Odour Threshold (value)

The minimum concentration of the substance in the air capable of being detected by the sense of smell. Normally expressed in parts per million (ppm) or milligrams per cubic metre (mg/m3). As odour threshold can deviate very significantly depending on various factors, they cannot be used to determine safe working levels.

pH

An indicative value on a continuous scale of 1 to 14 representing the degree of acidity (or alkalinity) of an aqueous solution of the product at a particular concentration. Where a value of 1 indicates a strong acid, 7 indicates neutrality (like pure water), and 14 a strong base. The concentration should be specified (usually one per cent). See also pHs.

Reactivity

The capacity to combine chemically with other substances. Reactivity is therefore important for the safe use and storage of hazardous materials. When reactive with water, it is particularly important information for the emergency authorities who often use water as an extinguishing and cleaning medium. As most substances are in some way reactive, the MSDS should address reactivity, the MSDS should address reactivity with common substances (for example, air or water).

Sensitisation

To become increasingly sensitive to a substance.

Sensitiser

A substance that causes (a substantial proportion of exposed people or animals) to develop an allergic reaction, or to become very sensitive to the substance (which may occur with minute quantities).

Standard on Uniform Scheduling of Drugs and Poisons (SUSDP)

The Standard for the Uniform Scheduling of Drugs and Poisons (SUSDP) as protected by the National Health and Medical Research Council (NHMRC) is the basis for State and Territory Poisons Act legislation (which may differ between regions in detail). The legislation applies restrictions at the point of sale.

There are nine Poisons Schedules listing substances or types of substances which require certain labelling and description, packaging (inner and outer), controls on advertising and supply, storage, and for some, the permitted level of impurities.

Synergism

The combined toxic effect is greater than the sum of each agent alone. An example is carbon tetrachloride and ethanol.

Toxic (Poisonous)

The ability of a substance to cause damage to cells or tissue whether or not at the point of contact.

Toxicity

Refers to the potential ability of a substance to cause deleterious (toxic) effects. (Low: causes readily reversible changes which disappear after exposure stops. Moderate: may cause reversible or irreversible changes to exposed tissue but not permanent injury. High: capable of causing death or permanent injury in normal use.)

United Nations (UN) Number

Also less commonly known as the Substance Identification Number (SI) and UN Transport Number, it is a system of four digit number, assigned to a substance, or a group of chemicals with similar hazardous properties (eg cresols).

Based on a common characteristic, the UN number provides a very useful and important link (via sub-section 9 of the ADG Code) to the Hazchem Code. Emergency Procedure Guides (to provide emergency information), dangerous goods class (to assist for safe handling and storage), the packaging group (to indicate the degree of hazard) and the method for safe packaging.

Vapour

The gas of a substance which is normally a solid or a liquid, and is also formed above a liquid or solid by evaporation.

Vapour Pressure

The pressure over a liquid created by its vapour. The higher the vapour pressure, the more volatile the substance.

These are substances or articles manufactured or used to produce a practical effect by explosion or a pyrotechnic effect.

Class 1 Dangerous Goods are broken up into the following categories:

CLASS

LABEL

Subsidiary

Risk Label

CLASS

DESCRIPTION

EXAMPLES

CLASS 1

EXPLOSIVES

1.1

1.2

1.3

1.4

1.5

Mass explosion

hazard

Projection hazard but not a mass explosion hazard

Fire hazard but not a projection or minor blast hazard

Substances or articles which present no significant hazard

Substances which have a mass explosive hazard, but are very insensitive

TNT,

Nitroglycerine

Ammunition, rockets, fireworks

Incendiary ammunition.

Some fuses, flares and fireworks.

Some fireworks, safety fuses.

Sulfur dioxide,

Chlorine

Class 2 - Gases

Class 2 Dangerous Goods are broken up into the following categories:

CLASS

LABEL

Subsidiary

Risk Label

CLASS

DESCRIPTION

EXAMPLES

CLASS 2

GASES

2.1

2.2

2.2

(and subsidiary risk 5.1)

2.3

Flammable gases

that are compressed, liquefied, or dissolved under pressure.

Non-toxic gases

and non-flammable gases.

Compressed oxidizing gas.

Toxic gases

Acetylene, liquid hydrogen, liquefied petroleum gas (LPG).

Natural Gas, (Methane)

Nitrogen,

carbon dioxide, Helium

Compressed

nitrous oxide,

compressed oxygen.

Sulfur dioxide,

Chlorine

Class 2.1 - Flammable Gases

such as LP gas, hydrogen, ethylene

These are gases which ignite on contact with a source of ignition.

Flammable gases burn when mixed with air and ignited. It is important to realise that these gases will only ignite when in a certain range of concentrations with air. This gas:air ratio is known as the Flammable or Explosive Range, and lies between the Lower Explosive Limit (LEL) and the Upper Explosive Limit (UEL). The wider the range, the more dangerous the gas.

Below

the LEL the mixture is too lean to burn.

Above

the UEL the mixture is too rich to burn.

* Flammable or Explosive Limits are expressed as a percentage of vapour in air.

Examples of Explosive Limits are:

LEL (%*)

UEL (%*)

Propane

2.2

9.5

Butane

1.6

8.4

Hydrogen

4.0

75.0

Ethylene

2.8

28.6

Acetylene

2.5

85

LPG

1.9

9.5

Methane

5

15

DENSITY

Most flammable gases are heavier than air and will settle in low areas such as drains, pits etc. Natural gas (methane) is an exception, with a density of 0.6. LPG has a density of 1.5 that of air. This means that LPG will form a pancake cloud on the ground.

PROPERTIES OF LP GAS

What is LP Gas?

LP Gas, or Liquefied Petroleum Gas, is composed mainly of the following hydrocarbons or a mixture of all or any three of them:

Propane

Butane

Propylene

Butylene

LP gases are obtained from stripping of natural gas and from fractionation of crude oil.

Boiling Point

At normal temperatures propane and butane are gases.

The boiling point of propane under normal conditions is minus 42°
C and that of butane is 0°
C.

Expansion

The expansion ratio of LP Gas is about 1:270. In other words 1 litre of LP Gas liquid expands to about 270 litres of vapour.

o

èo

LP Gas containers must be filled to only 80-85% of capacity depending on the size of the container. Overfilling is one of the greatest problems of the LP Gas industry.

Acetylene, C2H2, is used as a flammable gas for welding, cutting, localised heating and other purposes. A high temperature flame is produced when combusted with oxygen - 3,160°
C (the standard oxy-acetylene rig).

Acetylene vapour is lighter than air at 0.906 (air = 1). Acetylene is colourless with an ethereal odour.

The boiling point is -75°
C. This means the acetylene will readily form vapour in workplaces.

The flammability/explosive limits are: LEL 2.5%

UEL 80-85%

Acetylene is very dangerous as an explosive and flammable gas, only requiring a low energy source of ignition. Naked flames and smoking should not be allowed. Lines and equipment must be earthed.

The acetylene cylinder is full of a porous medium into which is compressed a solution of acetone. Store in dry, well ventilated areas, apart from oxygen. Transport on an open vehicle or in well ventilated area separate from the driver.

It is important to note that some flammable gas have a subsidiary risk of Toxic (2.3) or Corrosive (8).

While Class 2.2 gases are not flammable and are not toxic. Many have subsidiary risks such as oxidizing or corrosive. Some of these gases are liquefied, others are compressed.

Since many are also at low temperatures there is the risk of cold burns or frostbite.

Class 2.2 may cause asphyxiation if they replace oxygen in the atmosphere. This is especially true for low lying areas, since nearly all are heavier than air (in some cases up to 6 or 7 times heavier).

Many Class 2.2 gases are stored in liquid form e.g. Cryogenic gases stored below minus 150°
C. Because of the temperatures involved care must be taken to avoid frostbite. Examples are oxygen and nitrogen.

Some non-flammable compressed gases can have a subsidiary risk category of oxidizing (5.1) or corrosive (8).

These are gases which are liable to cause death or serious injury to human health if inhaled. Most have a perceptible, irritating odour.

Generally, most poison gases are heavier than air.

Most toxic gases have a perceptible irritating odour. Some of these gases can also have subsidiary risks such as flammable (2.1), oxidizing (5.1), corrosive (8), or in the case of nitrogen dioxide be both oxidizing and corrosive.

Gases such as chlorine or ammonia (used extensively in refrigeration) are very toxic to humans. Some examples of Class 2.3 gases and their Exposure Standard -Time Weighted Average (TWA) are:

Gas

TWA

Bromine

0.1 parts per million (ppm)

Chlorine

1.0 " " "

Hydrogen Sulphide

10 " " "

Ammonia

25 " " "

*Carbon Monoxide

50 " " "

* Although carbon monoxide is the least poisonous of the above it is potentially more dangerous because it has no smell.

Class 3 - Flammable Liquids

Class 3 Dangerous Goods are broken up into the following categories:

CLASS

LABEL

Subsidiary

Risk Label

CLASS

DESCRIPTION

EXAMPLES

No Label

No Label

CLASS 3

FLAMMABLE LIQUIDS

3PG I & II*

3PG III

C1

C2

Highly Flammable Liquid -

Liquids with

flashpoints <23°
C

Flammable Liquid -

Liquids with flashpoints between

23°
C and 60.5°
C

Combustible liquids with flashpoint

between 60.5°
C and 150°
C

Combustible liquids with flashpoints above 150°
C

Petroleum, solvent

naphtha, ether

Paints, mineral

turpentine,

Kerosene

Diesel Fuel,

Heating Oil

Lubricating oils

*Note: PG = Packing Group

Class 3 - Flammable Liquids

Class 3 Dangerous Goods are all those materials with a PRIMARYRISK of being a flammable liquid. It is the VAPOUR of flammable liquids which can burn if an ignition source is present. Ignition sources can be pilot lights, electrical spark, smokers, static electricity and hot surfaces.

Other classes of Dangerous Goods may also have a SUBSIDIARY RISK as flammable liquids.

PROPERTIES OF FLAMMABLE LIQUIDS

Flash Point

This is the temperature at which the flammable liquid will give off enough vapour to form an ignitable mixture with air. For example, petrol has a flash point of -32°
C. This means that vapour will be given off at temperatures above -32°
C that is capable of ignition.

Kerosene has a flashpoint of 50 degrees Celsius. Heat has to be present for kerosene to generate vapour for ignition. Diesel fuel has a flashpoint of 65 degrees C, and lubricating oil 200 degrees C.

EXAMPLES:

FLASHPOINTS OF COMMONLY USED SUBSTANCES:

White Spirit:

31-36 degrees C

Lubricating Oil:

200°
C

Diesel Fuel:

65°
C

Petrol:

-32°
C

Kerosene:

50°
C

VAPOUR DENSITY

Flammable liquid vapour is heavier than air. All gases and vapours with a vapour density greater than 1 are heavier than air and will fall towards the ground. These vapours and gases are dangerous because they fill low-lying spaces such as cellars, basements and service bays that are recessed below floor level. They can also "creep" along the ground and if these vapours and gases find an ignition source, they can 'flash back' to the flammable liquid or gas. Another possibility is the problem of exclusion of oxygen in low-lying spaces which can lead to asphyxiation (oxygen starvation). Petrol has a vapour density of about 2.5 to 3 times heavier than air.

FLAMMABILITY/EXPLOSIVE LIMITS

Flammable vapours will only burn in air at certain air/vapour mixtures.

An example is your car. Petrol will only burn between a vapour/air mixture of 1.4% and 7.6%.

The LOWER FLAMMABILITY limit of 1.4% is where your car is running too lean.

The UPPER FLAMMABILITY limit of 7.6% will make your car run rich, producing black smoke.

The aim of tuning your car is to make it operate within the 1.4% and 7.6% range, the FLAMMABILITY RANGE.

This explains why car engines are harder to start on winter mornings - when it is cold the petrol will not produce enough vapour to create an ignitable air/vapour mixture.

The Flammability Limits (sometimes called Explosive Limits) are expressed as percentages of the vapour in air. Listed below are the flammability limits of some commonly used flammable and combustible liquids.

PRODUCT

LOWER LIMIT

UPPER LIMIT

Petrol

1.4

7.6

Diesel Fuel

6.0

13.5

Kerosene

0.7

5.0

White Spirit

0.47

6.0

An important method of preventing fires and explosions with flammable liquids is to prevent the formation of flammable mixtures by keeping the liquid in a closed container, or by ventilation to prevent the vapour/air mixture reaching the flammable range.

Other terms related to flammability you might come across are:

(Auto) Ignition Temperature:

Is the minimum temperature required to initiate or cause self-sustained combustion.

Flash Point:

Is the minimum temperature of the liquid at which at which it gives off sufficient vapour to form an ignitable mixture with air.

Fire Point:

Is the lowest temperature at which a mixture of air and vapour continues to burn in an open container when ignited.

Spontaneous Combustion:

Can also arise when heat generated by a chemical reaction is prevented from escaping by some form of insulation. The trapped heat can increase the temperature of the flammable substance to its auto ignition temperature and ignite. Spontaneous combustion needs no external energy source.

TOXICITY

Some flammable liquids are also poisonous. Benzene is one example. Inhalation of the vapours of such substances may lead to death if the exposure is long enough at a high enough concentration.

Many flammable liquid vapours, while not toxic, can cause dizziness and headaches. Avoid breathing the fumes for extended periods.

Remember also that any gas or vapour can cause death by asphyxiation if it excludes oxygen from the air. The gas or vapour does not need to be toxic for this to happen.

Class 4 - Flammable Solids

Class 4 dangerous goods, generally described as "Flammable Solids", are substances which are liable to spontaneous combustion and substances which, on contact with water, emit flammable gases.

CLASS

LABEL

Subsidiary

Risk Label

CLASS

DESCRIPTION

EXAMPLES

CLASS 4

FLAMMABLE SOLIDS

4.1

4.2

4.3

Flammable Solids

Substances liable to spontaneous combustion

Substances which on contact with water emit flammable gases

Matches,

Magnesium

Aluminium powder

Yellow Phosphorus,

White Phosphorus,

Sodium metal

Powdered Zinc,

Calcium Carbide

Sodium metal,

Magnesium Alloy Powder

Class 4.1 - Flammable Solids

The substances in this Class are solids possessing the properties of being easily ignited by external sources, such as sparks and flames, and of being readily combustible or of being liable to cause or contribute to fire through friction or which may be self-reactive.

Class 4.2 - Spontaneously Combustible Substances

The substances in this class possess the common property of being liable to heat spontaneously and to ignite.

Some of these substances are more liable to spontaneous ignition when wetted by water, or in contact with moist air.

Some may also give off toxic gases when they are involved in a fire.

Class 4.3 - Dangerous When Wet

The substances in this class are either solids or liquids possessing the common property, when in contact with water, of evolving flammable gases.

In some cases these gases are liable to spontaneous ignition due to the heat liberated by the reaction.

Some of these substances evolve toxic gases when in contact with moisture, water or acids.

Class 5 - Oxidizers

Oxidizers are substances which give off oxygen or cause oxidation of other materials. Oxidation is a chemical reaction which results in a change in the electrical nature of chemicals.

PROPERTIES OF OXIDIZING AGENTS & ORGANIC PEROXIDES- CLASS 5

CLASS

LABEL

Subsidiary

Risk Label

CLASS

DESCRIPTION

EXAMPLES

CLASS 5

OXIDIZING AGENTS & ORGANIC PEROXIDES

5.1

5.2

Oxidizing Substances

Organic Peroxides

Calcium hypochlorite, Ammonia,

Hydrogen peroxide

Dry Chlorine

Methyl ethyl ketone peroxide (MEKP), Benzoyl peroxide

Oxidisers don't necessarily burn themselves but will support combustion.

5.1 Oxidizing agents

These substances which, although not necessarily combustible, may readily liberate oxygen or be the cause of oxidation processes. As a result fire may be started in other materials or the combustion of other materials may be stimulated with a resulting increase in the ferocity of the fire.

In other words, oxidizers don't necessarily burn themselves but will support combustion. Common examples of oxidizing agents are:

Calcium hypochlorite (pool chlorine)

All solid swimming pool chlorine is Class 5.1. Liquid pool chlorine or sodium hypochlorite belongs to Class 8. Calcium hypochlorite reacts explosively with flammable and combustible liquids such as distillate and brake fluid. The rate of reaction depends on the temperature.

Properties of Hydrogen Peroxide

The ingredient is hydrogen peroxide as a solution in water 59.5%. An oxidising agent with a subsidiary risk of corrosive. Used in paper pulp and textile bleaching and other purposes. A clear, colourless liquid with a sharp odour. Not combustible.

Corrosive if swallowed. Will burn the mouth, gullet and stomach. Corrosive to the eyes and skin. Irritant to the respiratory tract.

Store in original container. Keep temperature below 35°
C. Check with segregation requirements. Will probably need to be stored in a class 5.1 area. Keep away from heat. Avoid contamination, do not return unused chemical to container. Will liberate oxygen to support combustion.

First Aid: Seek medical advice!

Read the label and the MSDS

Eye wash stations and safety showers required

Eyes: Flush with water for 15 minutes.

Skin: Flush with water for 15 minutes, remove contaminated clothing.

Inhalation: Remove from exposure.

Ingestion: Do not induce vomiting. Rinse mouth with water, give water to drink.

Spills: Increase ventilation.

Work upwind.

Wear protective equipment.

Isolate area.

Contain spill. Prevent runoff to drains.

Dilute with water to 1% solution hydrogen peroxide.

Washdown to drain with approval.

Dispose of empty containers by washing with water and puncturing prior to disposal.

5.2 Organic peroxides

These are possibly the most dangerous of all Dangerous Goods. They contain their own oxygen in their chemical structure. They may be either liquids or solids. Most substances in this class are combustible and as such are unstable. They may detonate in closed containers in a fire situation.

Many organic peroxides may react dangerously with other substances. Violent decomposition may be caused by traces of impurities such as acids.

Decomposition of these substances may give rise to the development of toxic or flammable gases.

Examples of organic peroxides are:

* Benzoyl peroxide

* Methyl Ethyl Ketone Peroxide (MEKP)

Class 6 - Toxic Substances

Class 6 (Toxic Substances) is sub-divided as follows:

CLASS

LABEL

Subsidiary

Risk Label

CLASS

DESCRIPTION

EXAMPLES

CLASS 6 POISONOUS (TOXIC) SUBSTANCES

6.1

POISON

6.2

INFECTIOUS

SUBSTANCE

Poisonous (toxic) & harmful substances which are likely to cause death or serious injury if swallowed or inhaled, or by skin contact

Infectious Substances

Potassium cyanide

Calcium cyanide

Hydrofluoric Acid

Isocyanate (TDI)

Diethyl sulphate

Arsenic

Pesticides

Some vaccines, bacterial cultures

Class 6 - Toxic Substances

Class 6.1 Toxic Substances

These are substances which are liable to cause death or serious injury or to harm human health if swallowed or inhaled or by skin contact.

Class 6.2 Infectious substances

Infectious substances contain disease producing organisms. These substances are not covered by the Dangerous Goods Code.

Mode of Action of Poisonous Substances

Class 6 substances are harmful to the human body - they are said to be poison or toxic to humans.

There are many different ways in which substances may be poisonous - some affect our nervous system, or our breathing; others damage internal organs like our liver kidneys or reproductive organs; still others damage our blood or bone marrow. Some chemicals can have more than one effect in different parts of the body. So it is difficult to describe the actions of all poisons in a short and easy way.

Poisonous substances cover a wide variety of chemicals. For example, although they belong to different dangerous goods classification, Class 2.3 and Class 6.1 substances have the common property of being toxic.

Class 7 - Radioactive Substances

Each of the classes 1-8 present their own unique hazards. Class 1, explosives, Class 6.2, Infectious Substances, and Class 7, Radioactives are tightly restricted in industry and their use or handling requires special permits and expert training. If you handle any of these you must make sure that you receive proper training.

Radioactive materials emit radiation which may burn or otherwise damage cells and body tissue. People dealing with radioactive substances must be trained in their proper handling and storage.

CLASS

LABEL

Subsidiary

Risk Label

CLASS

DESCRIPTION

EXAMPLES

CLASS 7

RADIOACTIVE SUBSTANCES

7

Radioactive materials

Class 8 - Corrosive Substances

Class 8 Dangerous Goods (Corrosives) are solids or liquids possessing the common property of being able - more or less severely - to damage living tissue.

Many substances are sufficiently volatile to evolve vapour irritating to the nose and eyes. A few of these substances may produce toxic gases when decomposed by a very high temperatures. Also some substances in this Class can be toxic. Poisoning may result if they are swallowed.

CLASS

LABEL

Subsidiary

Risk Label

CLASS

DESCRIPTION

EXAMPLES

CLASS 8

CORROSIVES

8

Corrosive (ACID)

Corrosive (BASE)

Sulphuric acid

Nitric acid

Hydrochloric Acid

Sodium Hydroxide (Caustic soda)

Ammonia Solution

Oven Cleaner

Lime

NOTE: Corrosives that react with each other must be kept apart

Class 8 - Corrosives

Acids and bases are common examples of corrosive substances which easily damage living tissue on contact.

Some corrosives are volatile enough to give off vapours which can irritate the nose and eyes. A few may produce toxic gases when decomposed by very high temperatures. Some substances in this class can be toxic.

These substances are used in great quantities in industry and make up a significant proportion of industrial incidents.

An unfortunate feature of Class 8 is that both acids and bases are characterised as corrosive however together, acids and bases may react violently. Because of this acids must be kept separate from alkalies or bases (Alkalies are basic materials which dissolve in water).

Properties of Acids and Bases

ACIDS

An acid is a compound containing hydrogen that dissolves in water to produce hydrogen ions (H+) in solution. For example, hydrochloric acid (hydrogen chloride) forms hydrogen ions and chloride ions in solution. In symbols this would be:

HCI à
H+ + CI-

General properties of an acid when dissolved in water:

some have a sharp and sour taste

change the colour of certain plant dyes eg litmus from blue to red

some are poisonous

many are corrosive (they burn flesh)

Chemical properties of an acid:

·
react with many metals to form hydrogen gas

·
react with carbonates to form carbon dioxide

·
react with bases to form salts and water

Water will activate concentrated acids!

The reaction between acids and bases is called neutralisation because during

the reaction, both acids and bases lose their properties. The products (result)

Therefore it is virtually impossible to neutralise acids (and bases) with water.

Chemical methods are used instead. The three main agents used for

neutralising acids are:

(i) Sodium carbonate (soda ash) - Na

2CO3

(ii) Sodium bicarbonate - NaHCO

3

(iii) Calcium hydroxide (slaked lime) - Ca(OH)

2

Neutralisation must be done slowly or a vigorous reaction will result.

A salt is a compound formed by replacing the hydrogen ion of an acid by a metal ion. In the above example, the salt is potassium chloride. The potassium ion replaced the hydrogen ion in hydrochloric acid (hydrogen chloride).

Concentrated acids are almost pure with a very small percentage of water. Dilute acids contain a lot of water. In the complete absence of water, acids do not exhibit all the general properties listed above. The strength of an acid is a measure of how readily it can donate a proton (hydrogen ion).

Inhalation: Remove from area. Remove contaminated clothing. Perform recovery treatment such as coma position and CPR.

Ingestion: Rinse mouth with water. Give water or milk to drink. Do not

induce vomiting.

Spills: Increase ventilation.

Work upwind.

Wear protective equipment.

Isolate area.

Contain spill. Prevent runoff to drains.

Decontaminate spill with sand or soil. Prevent flow to

waterways.

Dilute with water, then use soda ash or slaked lime to

neutralise. Avoid vapour.

Dispose by washing to drain with excess water. Dispose of

waste through licensed waste disposer.

Class 9 - Miscellaneous Dangerous Goods

Class 9 (Miscellaneous Dangerous Goods) represent those materials which present a danger not covered by other classes. This class consists of dangerous goods which present a relatively low hazard if used incorrectly.

CLASS

LABEL

Subsidiary

Risk Label

CLASS

DESCRIPTION

EXAMPLES

CLASS 9

MISCELLANEOUS

DANGEROUS

GOODS

9

Miscellaneous dangerous goods

- Relatively Low Hazard

Dry Ice.

Packing Groups

I - High hazard

II - Medium hazard

III - Low Hazard

Class 3

Packing groups in Class 3’s are determined in the following ways:

Packing Group

Flash Point

(closed cup)

Initial boiling point

I

-

£
35°
C

II

<23°
C

>35°
C

III

³
23°
C - £
60.5°
C

>35°
C

Class 4

For packing groups for Class 4.1’s consult the list of chemicals which appear on pages 24 - 27 of Volume 2 of the Australian Dangerous Goods Code.

Packing groups for Class 4.2 are determined in the following way:

Potential pyrophoric and self-heating substances shall be tested and then assigned to a Packing Group in accordance with Clause 33.3 of the UN Recommendations - Manual of Tests and Criteria.

Packing Group I shall be assigned to all pyrophoric solids and liquids.

Packing Group II or III shall be assigned to self-heating substances which give positive results when tested with different sized cube samples.

Substances which in contact with water emit flammable gases shall be assigned to one of the three Packing Groups in accordance with the results of testing conducted under Clause 33.4 of the U.N. Recommendations - Manual of Tests and Criteria.

Packing Group I shall be assigned to any substance which reacts vigorously with water at ambient temperatures and demonstrates generally a tendency for the gas produced to ignite spontaneously or which reacts readily with water at ambient temperature such that the rate of evolution of flammable gas is equal to or greater than 10 litres per kilogram of substance over any one minute.

Eg. Sodium metal

Packing Group II shall be assigned to any substance which reacts readily with water at ambient temperatures such that the maximum rate of evolution of flammable gas is equal to or greater than 20 litres per kilogram of substance per hour, and which does not meet the criteria for Packing Group I.

Eg. Calcium metal

Packing Group III shall be assigned to any substance which reacts slowly with water at ambient temperatures such that the maximum rate of evolution of flammable gas is equal to or greater than 1 litre per kilogram of substance per hour, and which does not meet the criteria for Packing Groups I or II.

Eg. Aluminium silicon powder, uncoated

Class 5

Packing groups for 5.1 are assigned according to the following:

Oxidizing substances (Class 5.1) shall be assigned to one of the three Packing Groups according to the results of testing conducted under section 34 of the U.N. Recommendations - Manual of Tests and Criteria.

Packing groups for Class 5.2’s are assigned according to the following:

All Organic Peroxides (Class 5.2) have been assigned to Packing Group II.

Class 6

Packing group for Class 6.1’s are assigned according to the following:

Packing Group

Oral toxicity

LD50 (mg/kg)

Dermal toxicity

LD50 (mg/kg)

Inhalation toxicity by dusts and mists

LD50 (mg/L)

I

£
5

£
40

£
0.5

II

> 5-50

> 40-200

> 0.5-2

III

Solids > 50-200

> 200-1000

> 2-10

Liquids > 50-500

Class 8

Packing groups for Class 8’s are assigned according to the following:

(a) Packing Group I

(i) Substances which cause visible necrosis of skin tissue at the site of contact when tested for a period of 3 minutes or less; or

(ii) Substances which cause visible necrosis of skin tissue at the site of contact when tested for a period of more than three minutes but not more than sixty minutes, and in addition have an inhalation toxicity in the vapour phase corresponding to an LC50 greater than 50ppm but not more than 200ppm.

Note: Substances with an inhalation toxicity in the vapour phase corresponding to an LC50 of equal to or less than 50ppm should be considered primarily as a toxic hazard.

(b) Packing Group II

(i) Substances which cause visible necrosis of skin tissue at the site of contact when tested for a periods of more than three minutes but not more than 60 minutes; or

(ii) Liquid waste substances that have a pH less than 2.0 or greater than 12.5.

(c) Packing Group III

(i) Substances which cause visible necrosis of skin tissue at the site of contact when tested for a period of more than sixty minutes but not more than four hours; or

(ii) Substances which do not cause visible necrosis after the period specified in (i) of this part (c) but which corrode the test metals at a rate greater than 6.25mm per year.

Hazchem Signs

The HAZCHEM Code System was first developed in Britain by the British Fire System.

HAZCHEM Codes are developed and assigned to dangerous goods after careful study of their properties and characteristics.

The HAZCHEM Code is used on vehicles that transport in bulk. It is also used at workplaces that store dangerous goods .

Composite Warning Notice for Packaged Dangerous Goods

need to insert label

Composite Warning Notice for Bulk Dangerous Goods

The HAZCHEM Code provides advice on:

(a) the type of medium to be employed in combating a dangerous goods incident where product has escaped, been spilt or is involved in fire.

(b) possible violent reaction and hazards posed to the local population.

(c) types of personal protection to be worn by persons combating the incident.

The number indicates the type of medium to be used by the fire services:

1 - Solid streams of water

2 - Water, fog or fine water spray

3 - Water based foam

4 - Dry agent

A medium of higher number may be used but a medium of lower number than indicated can not be used.

The first letter indicates the type of personal protection to be worn, the possibility of violent reaction and whether the goods and the medium employed should be contained or the goods diluted.

"Contain" attempts to achieve this by confining the material within finite bounds and minimising environmental impact. It also allows recovery of the material where such a procedure is safe and practicable.

"Violent Reaction" may occur through such agencies as decomposition, ignition of vapours, acceleration of combustion due to involvement of an oxidizing agent or reaction with water.

The second letter is E. This indicates that evacuation of persons in the neighbouring areas must be taken into consideration. Persons in the immediate area of the incident should always be evacuated to a safer location irrespective of whether the letter E appears in the HAZCHEM Code.

Key to the HAZCHEM Code

need to insert hazchem scale.

Segregation

If dangerous goods are to be stored together then there are some general conditions of storage that must be adhered to.

To use Table 1, select two of the Classes of dangerous goods to be kept in the mixed-class storage area. Locate the first Class on the top line of class numbers, and the second Class in the column on the left side of the table. Read the code at the intersection of the line and column.

KEYS TO THE CODES

NA

means that separation or segregation are Not Applicable to the two Classes, and they may be stored in the same area.
However, any overriding requirements of Part 5 to 11 of the Regulations must be complied with.

SG

means that the two Classes must be SeGregated (i.e. kept apart) from each other by a distance of at least three metres.

Again, any overriding requirements in Parts 5 to 11 of the Regulations must be complied with.

FS

means that the two Classes must be Fire Separated. Fire separation must be provided by:
- walls of at least 4-hour fire resistance (FRL) surrounding the storage area for one of the Classes of dangerous goods. The separated storage areas must comply with the requirements of Parts 5 to 11 of the Regulations that are appropriate to the particular Class of dangerous goods.

or

- a separation distance in the same area of at least five metres. Check Parts 5 to 11 of the Regulations to make sure that greater distances or separate storage are not required. Electrical equipment in the storage area must be suitable for use in a Zone 2 Hazardous Area as defined in AS 2430 - Classification of Hazardous Areas.

PR

means that the two Classes are Prohibited in the same storage area. As well, they must not be stored in adjoining areas which are attached to each other. The two classes must be stored in separate areas at least ten metres apart, or at any greater distance required by Parts 5 to 11 of the Regulations.

The storage areas for Classes of dangerous goods rated SG, FS or PR above must be:

ventilated;

have a spill-collection measures if liquid goods are kept; and

provide with explosion vents and electrical equipment suitable for a Zone 2 Hazardous Area if any of the stored goods generate flammable gases, vapours or combustible dust.

Activity:

1. (a) What is a Class Label?

(b) Draw a Class Label for a Flammable Gas.

2. (a) What is a subsidiary risk?

(b) Draw a Class Label for a Corrosive with a Toxic subsidiary risk.

3. (a) What do the following Classes mean:

2.1 4.3

7 9

6.1 4.1

4.2 3

(b) What do the following mean:

Class 2.2 - Subsidiary Risk 5.1

Class 3 - Subsidiary Risk 8

Class 8 - Subsidiary Risk 6.1

4. (a) What is a HAZCHEM Code used for?

(b) What do the following HAZCHEM Codes mean?

4[Z]E

2S

3WE

1PE

4[T]

3XE

5. Interpret the following Composite signs.

3WE

2P

4[T]E

6. Your workplace stores a number of dangerous goods together in the one area. Your employer is worried that one day there might be an incident involving the chemical store. He asks you if the chemicals might need to be segregated.